This invention relates to silver halide photographic materials containing solubilized antifoggants. More specifically it relates to non-photothermographic silver halide materials containing solubilized antifoggants.
Problems with fogging have plagued the photographic industry from its inception. Fog is a deposit of silver or dye that is not directly related to the image-forming exposure, i.e., when a developer acts upon an emulsion layer, some reduced silver is formed in areas that have not been exposed to light. Fog can be defined as a developed density that is not associated with the action of the image-forming exposure, and is usually expressed as xe2x80x9cD-minxe2x80x9d, the density obtained in the unexposed portions of the emulsion. Density, as normally measured, includes both that produced by fog and that produced as a function of exposure to light. It is known in the art that the appearance of photographic fog related to intentional or unintentional reduction of silver ion (reduction sensitization) can occur during many stages of preparation of the photographic element including silver halide emulsion preparation, spectral/chemical sensitization of the silver halide emulsion, melting and holding of the liquid silver halide emulsion melts, subsequent coating of silver halide emulsions, and prolonged natural and artificial aging of coated silver halide emulsions. The chemicals used for preventing fog growth as a result of aging or storage are generally known as emulsion stabilizers.
The control of fog, whether occurring during the formation of the light-sensitive silver halide emulsion, during the spectral/chemical sensitization of those emulsions, during the preparation of silver halide compositions prior to coating on an appropriate support, or during the aging of such coated silver halide compositions, has been attempted by a variety of means. Mercury-containing compounds, such as those described in U.S. Pat. Nos. 2,728,663; 2,728,664; and 2,728,665, have been used as additives to control fog. Thiosulfonates and thiosulfonate esters, such as those described in U.S. Pat. Nos. 2,440,206; 2,934,198; 3,047,393; and 4,960,689, have also been employed. Organic dichalcogenides, for example, the disulfide compounds described in U.S. Pat. Nos. 1,962,133; 2,465,149; 2,756,145; 2,935,404; 3,184,313; 3,318,701; 3,409,437; 3,447,925; 4,243,748; 4,463,082; and 4,788,132 have been used not only to prevent formation of fog, but also as desensitizers and as agents in processing baths and as additives in diffusion transfer systems.
However, despite all the efforts in this field there still remains a need for compounds which act as effective antifoggants in photographic elements which are stored under high temperature conditions. There is particularly a need for antifoggants which are water soluble and, thus, are safer to utilize during manufacture of the photographic elements.
This invention provides a silver halide photographic element comprising at least one silver halide emulsion layer and further comprising an antifoggant represented by the following Structure I:

wherein R1 is an aliphatic or cyclic group, R2 and R3 are independently hydrogen or bromine as long as at least one of them is bromine, L is a divalent linking group, m and n are independently 0 or 1, and SG is a solubilizing group with a pKa of 8 or less. This invention further provides silver halide emulsions comprising said antifoggants.
The photographic elements of this invention demonstrate reduced fogging during chemical sensitization and enhanced fog retardation of liquid emulsions during high temperature holding. The water soluble antifoggants minimize the need for expensive and time-consuming preparation of solid-particle dispersions, as well as minimize the need for volatile organic solvents. Use of these materials also eliminates the need to use environmentally undesirable heavy metal antifoggant salts such as mercuric salts.
The silver halide photographic elements of this invention include one or more water-soluble or water-dispersible antifoggants containing a solubilizing group with a pKa of 8 or less. These compounds are represented by the following Structure I:

wherein R1 is a substituted or unsubstituted aliphatic or cyclic group of any size as long as the antifoggant remains soluble or readily dispersible in water. Substituted or unsubstituted aliphatic groups for R1 include monovalent groups having 1 to 20 carbon, nitrogen, sulfur, and oxygen atoms in the chain including, but not limited to, chains that include one or more substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, substituted or unsubstituted alkenylene groups having 2 to 20 carbon atoms, substituted or unsubstituted alkylenearylene groups having 7 to 20 carbon atoms in the chain, and combinations of any of these groups, as well as combinations of these groups that are connected with one or more amino, amido, carbonyl, sulfonyl, carbonamido, sulfonamido, thio, oxy, oxycarbonyl, oxysulfonyl, and other connecting groups that would be readily apparent to one skilled in the art. The various types of useful aliphatic groups would be readily apparent to one skilled in the art. Preferred aliphatic groups for R1 include substituted or unsubstituted t-butyl groups and trifluoromethyl groups.
R1 can also be substituted or unsubstituted cyclic groups including substituted or unsubstituted carbocyclic aryl groups having 6 to 14 carbon atoms to form the cyclic ring, substituted or unsubstituted cycloalkylene groups (having 5 to 10 carbon atoms to form the cyclic ring), and heterocyclic groups (having 5 to 10 carbon, nitrogen, sulfur, or oxygen atoms to form the cyclic ring), both aromatic and non-aromatic. The various types of cyclic groups would be readily apparent to one skilled in the art.
Preferred cyclic groups for R1 include substituted or unsubstituted aryl groups having 6 to 10 carbon atoms to form the cyclic ring. Substituted or unsubstituted phenyl groups are most preferred. Methyl groups are preferred substituents on the phenyl group.
In Structure I, R2 and R3 are independently hydrogen or bromine as long as one of them is bromine. Preferably, both R2 and R3 are bromine.
In addition, L is a substituted or unsubstituted divalent linking group, and more preferably an aliphatic linking group that can have the same definition as R1 except that L is divalent. Thus, one skilled in the art would be able to determine suitable L groups that would serve the desired purpose while maintaining compound water solubility or dispersibility. Preferably, L is xe2x80x94NH-alkylene wherein xe2x80x9calkylenexe2x80x9d is substituted or unsubstituted and has 1 to 10 carbon atoms (more preferably 1 to 3 carbon atoms).
Substituents on R1 and L can be any chemical moiety that would not adversely affect the desired function of the antifoggant and can include, but are not limited to, alkyl, aryl, heterocyclic, cycloalkyl, amino, carboxy, hydroxy, phospho, sulfonamido, sulfo, halo, and other groups that would be readily apparent to one skilled in the art. The number of substituents is limited only by the number of available valences (available hydrogen atoms). Alkyl groups are preferred substituents for cyclic R1 groups. However, as would be apparent, the antifoggants can have multiple sulfo, carboxy, phospho, and sulfonamido groups that impart water solubility to the molecule. Further, in Structure I, m and n are independently 0 or 1, and preferably, both are 1.
SG can be any suitable solubilizing group which has a pKa of 8 or less and which does not interfere with the antifogging activity of the compound. SG may be in the free acid form or it may be a salt, particularly a suitable metal (for example, alkali metal salt) or ammonium ion salt. Preferably, SG is a salt. When SG is in its free acid form, the salt can be generated in situ by neutralization with any basic material commonly used by one skilled in the art. Preferably SG is a carboxy, phospho, sulfo, or sulfonamido group. When SG is a sulfonamido group, it may be xe2x80x94SO2Nxe2x88x92COR4M+, or xe2x80x94NSO2R4M+ with R4 being a substituted or unsubstituted aliphatic or cyclic group that is defined the same as for R1, although R1 and R4 can be the same or different in a particular compound. Preferably, SG is a carboxy or sulfo group (or salts thereof, particularly when both m and n are 1.
M+ is a suitable cation such as a metal cation (preferably alkali metal ion) or an ammonium ion. When M+ is a hydrogen atom, the resulting free acid can be easily solubilized by neutralization with any convenient base, such as, for example, potassium hydroxide or sodium bicarbonate.
Representative antifoggants useful within the practice of this invention include the following compounds: 
The compounds represented by Structure I can be prepared using starting materials and procedures that would be readily apparent to one skilled in the art. For example, compounds wherein m is 1 (and n is 0 or 1) can be prepared by reacting a salt of a sulfinic acid (such as p-toluenesulfinic acid, sodium salt) with a 2-bromomethylcarbonyl derivative, followed by bromination of the resulting sulfone using molecular bromine or another suitable brominating agent.
Instead of using the salt of a sulfinic acid, an aromatic or aliphatic thiol can be condensed with the 2-bromomethylcarbonyl derivative followed by oxidation of the thioether to a sulfone and then subsequent bromination.
Some 2-bromomethylcarbonyl derivatives can be prepared by reacting bromoacetylbromide with amines such as taurine, as described in U.S. Pat. No. 5,091,298 (Parton et al), with glycine, as described in the Journal of the Korean Society of Textile Engineers and Chemists, p 13, December 1981 (Hwang et al), or with methanesulfonamide, as described in U.S. Pat. No. 5,620,989 (Harrison et al).
Monobromination can be achieved by using only one equivalent of a source of bromine, using a less active brominating agent, or by adjusting reaction conditions as one skilled in the art would readily understand.
By xe2x80x9cwater-solublexe2x80x9d or xe2x80x9cwater-dispersiblexe2x80x9d in defining the antifoggants is meant that the compounds are readily dissolved or dispersed in water. Therefore, their use in silver halide emulsions and photographic elements alleviates the need for volatile organic solvents and circumvents the disadvantages of using solid particle dispersions. In order to be xe2x80x9cwater-solublexe2x80x9d or xe2x80x9cwater-dispersiblexe2x80x9d, it should be possible to add between 0.1 g and 500 g of the antifoggant to 1000 mL of water. Optimally, it should be possible to add between 50 g and 200 g of the antifoggant to 1000 mL of water The antifoggants can be used individually or in combination in the elements of this invention. Generally, they are present in an amount of at least 0.0001 mol/mol of total silver. Preferably, they are present in an amount of from about 0.001 to about 0.1 mol/mol of total silver.
The antifoggant compounds may be added to any layer where they are in reactive association with the silver halide. By xe2x80x9cin reactive association withxe2x80x9d it is meant that the compounds must be contained in the silver halide emulsion layer or in a layer whereby they can react or interact with, or come in contact with, the silver halide emulsion. Preferably, the antifoggants are included in the one or more emulsion layers, but during manufacture, they can also be incorporated into interlayers, underlayers, and protective topcoat layers on the frontside of the support. If they are placed in a non-emulsion layer, they tend to migrate into the emulsion layer(s) where they become effective in reducing Dmin. The antifoggant compounds may be added to the photographic emulsion using any technique suitable for this purpose.
The photographic emulsions used in this invention are generally prepared by precipitating silver halide crystals in a colloidal matrix by methods conventional in the art. The colloid is typically a hydrophilic film forming agent such as gelatin, alginic acid, or derivatives thereof.
The crystals formed in the precipitation step are washed and then chemically and spectrally sensitized by adding spectral sensitizing dyes and chemical sensitizers, and by providing a heating step during which the emulsion temperature is raised, typically from 40xc2x0 C. to 70xc2x0 C., and maintained for a period of time. The precipitation and spectral and chemical sensitization methods utilized in preparing the emulsions employed in the invention can be those methods known in the art.
Chemical sensitization of the emulsion typically employs sensitizers such as: sulfur-containing compounds, e g., allyl isothiocyanate, sodium thiosulfate and allyl thiourea; reducing agents, e.g., polyamines and stannous salts; noble metal compounds, e.g., gold, platinum; and polymeric agents, e.g., polyalkylene oxides. As described, heat treatment is employed to complete chemical sensitization. Spectral sensitization is effected with a combination of dyes, which are designed for the wavelength range of interest within the visible or infrared spectrum. It is known to add such dyes both before and after heat treatment.
After spectral sensitization, the emulsion is coated on a support. Various coating techniques include dip coating, air knife coating, curtain coating, and extrusion coating.
The antifoggants may be added to the silver halide emulsion at any time during the preparation of the emulsion, i.e., during precipitation, during or before chemical sensitization, or during final melting and co-mixing of the emulsions and additives for coating. More preferably, these compounds are added after precipitation and washing and most preferably during or directly after chemical sensitization of the final melt.
The antifoggants may be utilized in addition to any conventional emulsion stabilizer or antifoggant as commonly practiced in the art. Combinations of the antifoggants of the invention may also be utilized.
The elements of the invention are photographic elements as opposed to photothermographic elements. The imaging arts have long recognized that the field of photothermography is clearly distinct from that of photography. Photothermographic materials differ significantly from conventional silver halide photographic materials that require processing with aqueous processing solutions to provide a visible image.
In photothermographic imaging materials, a visible image is created solely by heat as a result of the reaction of a developer incorporated within the material. Heating at 50xc2x0 C. or more is essential for this dry development. In contrast, conventional photographic imaging materials require contact with an aqueous processing solution. Heat may be utilized in addition to the processing solution but at more moderate temperatures (generally from 30xc2x0 C. to 50xc2x0 C.) to provide a visible image.
In photothermographic materials, all of the xe2x80x9cchemistryxe2x80x9d for imaging is incorporated within the material itself For example, such materials include a developer (that is, a reducing agent for the reducible silver ions) while conventional photographic materials usually do not. Even in so-called xe2x80x9cinstant photographyxe2x80x9d, the developer chemistry is physically separated from the photosensitive silver halide until development is desired. Moreover, in photothermographic materials, the unexposed silver halide generally remains intact after development and the material must be stabilized against further imaging and development. In contrast, silver halide is removed from conventional photographic elements after solution development to prevent further imaging (that is, in the aqueous fixing step).
The antifoggants of this invention are used in silver halide photographic elements wherein processing is initiated, at least in part, using an aqueous processing solution, as opposed to using solely heat. The silver halide photographic elements of the invention may utilize either low volume processing systems or conventional processing systems.
Low volume systems are those where film processing is initiated by contact to a processing solution, but where the processing solution volume is comparable to the total volume of the imaging layer to be processed. This type of system may include the addition of non solution processing aids, such as the application of heat or of a laminate layer that is applied at the time of processing. Conventional photographic systems are those where film elements are processed by contact with conventional photographic processing solutions, and the volume of such solutions is very large in comparison to the volume of the imaging layer.
Low volume processing is defined as processing where the volume of applied developer solution is between about 0.1 to about 10 times, preferably about 0.5 to about 10 times, the volume of solution required to swell the photographic element. This processing may take place by a combination of solution application, external layer lamination, and heating. The low volume system photographic element may receive some or all of the following treatments:
(I) Application of a solution directly to the film by any means, including spray, inkjet, coating, gravure process, and the like.
(II) Soaking of the film in a reservoir containing a processing solution. This process may also take the form of dipping or passing an element through a small cartridge.
(III) Lamination of an auxiliary processing element to the imaging element. The laminate may have the purpose of providing processing chemistry, removing spent chemistry, or transferring image information from the latent image recording film element. The transferred image may result from a dye, dye precursor, or silver containing compound being transferred in an image-wise manner to the auxiliary processing element.
(IV) Heating of the element by any convenient means, including a simple hot plate, iron, roller, heated drum, microwave heating means, heated air, vapor, or the like. Heating may be accomplished before, during, after, or throughout any of the preceding treatments I-III. Heating may cause processing temperatures ranging from room temperature to 100xc2x0 C.
Conventional photographic elements in accordance with the invention can be processed in any of a number of well-known photographic processes utilizing any of a number of well-known conventional photographic processing solutions, described, for example, in the Research Disclosures referenced hereafter, or in T. H. James, editor, The Theory of the Photographic Process, 4th Edition, Macmillan, New York, 1977. The development process may take place for any length of time and any process temperature that is suitable to render an acceptable image.
Some common black-and-white developing agents include the p-aminophenols, such as Metol, the polyhydroxybenzenes such as hydroquinone and catechol, the pyrazolidones (phenidones), and ascorbic acid. These developers may be utilized alone or in combination. In black-and-white processing the development step is generally followed by a fixing step and optionally a washing step.
In the case of processing a negative working color element, the element is treated with a color developer (that is, one which will form the colored image dyes with the color couplers), and then with a oxidizer and a solvent to remove silver and silver halide. In the case of processing a reversal color element, the element is first treated with a black-and-white developer (that is, a developer which does not form colored dyes with the coupler compounds) followed by a treatment to fog silver halide (usually chemical fogging or light fogging), followed by treatment with a color developer. Preferred color developing agents are p-phenylenediamines. Especially preferred are:
4-amino-N,N-diethylaniline hydrochloride,
4-amino-3-methyl-N,N-diethylaniline hydrochloride,
4-amino-3-methyl-N-ethyl-N-(2-(methanesulfonamido) ethylaniline sesquisulfate hydrate,
4-amino-3-methyl-N-ethyl-N-(2-hydroxyethyl)aniline sulfate,
4-amino-3-xcex1-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride and
4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid.
Development is usually followed by the conventional steps of bleaching, fixing, or bleach-fixing to remove silver or silver halide, washing, and drying.
Other processing methods useful with the current invention include less conventional processors such as those described in U.S. Pat. No. 5,890,028, a drum processor such as the Kodak RS-11 Drum Processor, or a wave processor which processes a photographic material by loading the material into a chamber, introducing a metered amount of processing solution into the chamber, and rotating the chamber in a fashion which forms a wave in the solution through which the material passes. The appropriate solution for each processing stage is added and removed sequentially from the processing space and can be treated for disposal as described in the current invention. The wave processor is described in more detail in U.S. application Ser. No. 09/920,495, filed Aug. 1, 2001.
Another processor and processing method with which the current invention is particularly useful is the merged process described in U.S. application Ser. No. 10/012,673 filed Oct. 30, 2001 of Peter J. Twist titled xe2x80x9cProcessing Photographic Materialxe2x80x9d. This processing method for silver halide photographic material comprises loading the material into a chamber, introducing a metered amount of a first processing solution into the chamber, and processing the photographic material with the first processing solution. It then comprises introducing a metered amount of a second processing solution into the chamber without removing the first processing solution so that at least part of the whole volume of the second processing solution is provided by the first processing solution and processing the photographic material with the second processing solution. The merged method further comprises, after processing the photographic material with the second processing solution, introducing a metered amount of a third processing solution into the chamber without removing any processing solution remaining from the preceding processing solution or solutions so that at least part of the total volume of the third processing solution is provided by the preceding processing solution or solutions and processing the photographic material with the third processing solution.
Using the merged solution processing method it is possible to add all of the processing solutions except the wash solution on top of one another in the correct sequence without removing the previous solution. Thus, the whole of the previous solution is mixed with the next solution. The method is preferably carried out in a high agitation single use processor which processes one film at a time with small volumes similar to those used to replenish continuous processors with tanks of several liters. Thus, a developer solution may be added to the tank of the single use processor, and after development is complete, a bleach solution, for example, is added to the developer solution to transform the developer into a bleach solution, then a fix solution is added to the developer plus bleach solution to convert it into a bleach-fix solution. The previous solution acts as a diluent for the next solution which means that the next solution can be more concentrated than it would be if it were used alone. This means that the total volume used in the process can be less than that used if each solution is removed after the particular stage it performs is complete.
With negative-working silver halide, the processing steps provide a negative image. One type of such element, referred to as a color negative film, is designed for image capture. Speed (the sensitivity of the element to low light conditions) is usually critical to obtaining sufficient image in such elements. Such elements are typically silver bromoiodide emulsions coated on a transparent support and are sold packaged with instructions to process in known color negative processes such as the Kodak C-41 process as described in The British Journal of Photography Annual of 1988, pages 191-198. If a color negative film element is to be subsequently employed to generate a viewable projection print as for a motion picture, a process such as the Kodak ECN-2 process described in the H-24 Manual available from Eastman Kodak Co. may be employed to provide the color negative image on a transparent support. Color negative development times are typically 3xe2x80x2 15xe2x80x3 or less and desirably 90 or even 60 seconds or less.
Another type of color negative element is a color print. Such an element is designed to receive an image optically printed from an image capture color negative element. A color print element may be provided on a reflective support for reflective viewing (e.g., a snapshot) or on a transparent support for projection viewing as in a motion picture. Elements destined for color reflection prints are provided on a reflective support, typically paper, employ silver chloride emulsions, and may be optically printed using the so-called negative-positive process where the element is exposed to light through a color negative film which has been processed as described above. The element is sold packaged with instructions to process using a color negative optical printing process, for example the Kodak RA-4 process, as generally described in PCT WO 87/04534 or U.S. Pat. No. 4,975,357, to form a positive image. Color projection prints may be processed, for example, in accordance with the Kodak ECP-2 process as described in the H-24 Manual. Color print development times are typically 90 seconds or less and desirably 45 or even 30 seconds or less.
A reversal element is capable of forming a positive image without optical printing. To provide a positive (or reversal) image, the color development step is preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and followed by uniformly fogging the element to render unexposed silver halide developable. Such reversal elements are typically sold packaged with instructions to process using a color reversal process such as the Kodak E-6 process as described in The British Journal of Photography Annual of 1988, page 194. Alternatively, a direct positive emulsion can be employed to obtain a positive image.
The above elements are typically sold with instructions to process using the appropriate method such as the mentioned color negative (Kodak C-41), color print (Kodak RA-4), or reversal (Kodak E-6) process.
The photographic elements can be black and white such as radiographic films, aerial films, black-and-white motion picture films, duplicating and copy films, graphic arts films, positive- and negative-working microfilms, and amateur and professional continuous tone black-and-white films. The antifoggants are particularly suitable for use in graphic arts films which develop to give very high image quality xe2x80x9chard dotsxe2x80x9d through use of hydrazide nucleating agents coated in the film. Hydrazide nucleating agents are well known to those skilled in the art. Some suitable hydrazide nucleating agents are described in U.S. Pat. Nos. 6,143,462; 6,228,566; and 6,245,480; GB Application No. 0102880.2 filed Feb. 6, 2001 and GB Application 0014329.7 filed Jun. 12, 2000. These bring about ultra high contrast by reacting with oxidized developer from initially developing light-imaged grains to generate agents which trigger developability of the immediately adjacent grains. It is especially necessary that the silver halide emulsions used in such films have a low level of fogged grains, i.e., those developable without first receiving light exposure, because the amplification caused by the nucleating agents can otherwise cause microscopic black spots known as xe2x80x9cpepper fogxe2x80x9d, which degrade the image. The solubilized antifoggants of the invention are particularly useful in such high contrast elements when used in combination with dichalcogenide antifoggants such as those described in U.S. Pat. Nos. 5,219,721 and 5,418,127.
The elements of the invention can be single color elements or multicolor elements. Multicolor elements contain image dye-forming units sensitive to each of the three primary regions of the spectrum. Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer.
A typical multicolor photographic element comprises a support bearing a cyan dye image-forming unit comprised of at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta dye image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler, and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element can contain additional layers, such as filter layers, interlayers, overcoat layers, and subbing layers.
If desired, the photographic element can be used in conjunction with an applied magnetic layer as described in Research Disclosure, November 1992, Item 34390 published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND, the contents of which are incorporated herein by reference. Further, the photographic elements may have an annealed polyethylene naphthalate film base such as described in Hatsumei Kyoukai Koukai Gihou No. 94-6023, published Mar. 15, 1994 (Patent Office of Japan and Library of Congress of Japan) and may be utilized in a small format system, such as described in Research Disclosure, June 1994, Item 36230 published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND, and such as the Advanced Photo System, particularly the Kodak ADVANTIX films or cameras.
In the following Table, reference will be made to (1) Research Disclosure, December 1978, Item 17643, (2) Research Disclosure, December 1989, Item 308119, (3) Research Disclosure, September 1994, Item 36544, and (4) Research Disclosure, September 1996, Item 38957, all published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND, the disclosures of which are incorporated herein by reference. The Table and the references cited in the Table are to be read as describing particular components suitable for use in the elements of the invention. The Table and its cited references also describe suitable ways of preparing, exposing, processing and manipulating the elements, and the images contained therein. Photographic elements and methods of processing such elements particularly suitable for use with this invention are described in Research Disclosure, February 1995, Item 37038, published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND, the disclosure of which is incorporated herein by reference.
The photographic elements can be incorporated into exposure structures intended for repeated use or exposure structures intended for limited use, variously referred to as single use cameras, lens with film, or photosensitive material package units.
Photographic silver halide elements utilize more silver halide than do photothermographic materials. In photothermographic materials, only a small amount of silver halide is used to capture light and a non-photosensitive source of reducible silver ions (for example, a silver carboxylate) is used to generate the visible image using thermal development. Thus imaged, the photosensitive silver halide serves as a catalyst for the physical development process involving the non-photosensitive source of reducible silver ions and the incorporated reducing agent. In contrast, conventional wet-processed photographic materials use only one form of silver (that is, silver halide) that, upon chemical development, is itself converted into the silver image, or that upon physical development requires addition of an external silver source (or other reducible metal ions that form black images upon reduction to the corresponding metal). Thus, photothermographic materials require an amount of silver halide per unit area that is only a fraction of that used in conventional wet-processed photographic materials. Additionally the silver halide to organic Ag salt ratio is very different for the two types of imaging materials. The two are defined as follows. AgX is all the silver halide in an element either added via ex-situ methods (preformed AgX) or generated in-situ by addition of free halide to the organic silver salt. AgR is the reducible silver ions coming from a non-photosensitive source. In conventional photographic elements AgX/AgR is always greater than 1 on a mass basis or a mass/surface area basis. In photothermographic systems AgX/AgR is always less than 1 on a mass basis or a mass/surface area basis. Therefore, the silver halide photographic elements of the invention generally have, over the multiplicity of element layers, a ratio of AgX/AgR greater than 1 and photothermographic systems generally have, over the multiplicity of element layers, a ratio of AgX/AgR less than 1.
These and other distinctions between photothermographic and photographic materials are described in Imaging Processes and Materials (Neblette""s Eighth Edition), noted above, Unconventional Imaging Processes, E. Brinckman et al (Eds.), The Focal Press, London and New York, 1978, pp. 74-75, in Zou et al, J. Imaging Sci. Technol. 1996, 40, 94-103, and in M. R. V. Sahyun, J. Imaging Sci. Technol. 1998, 42, 23.
The silver halide emulsions utilized may be of any silver halide composition, including but not limited to silver bromide, silver bromoiodide, silver chloride, silver chlorobromide, and silver chloroiode. Preferably the silver halide emulsions utilized in this invention are bromoiodide emulsions.
The silver halide emulsions can contain grains of any size and morphology. Thus, the grains may take the form of cubes, octahedrons, cubo-octahedrons, or any of the other naturally occurring morphologies of cubic lattice type silver halide grains. Further, the grains may be irregular such as spherical grains or tabular grains.
Especially useful in this invention are tabular grain silver halide emulsions. Tabular grains are those having two parallel major crystal faces and having an aspect ratio of at least 2. The term xe2x80x9caspect ratioxe2x80x9d is the ratio of the equivalent circular diameter (ECD) of a grain major face divided by its thickness (t). Tabular grain emulsions are those in which the tabular grains account for at least 50 percent (preferably at least 70 percent and optimally at least 90 percent) of the total grain projected area. Preferred tabular grain emulsions are those in which the average thickness of the tabular grains is less than 0.3 micrometer (preferably thinxe2x80x94that is, less than 0.2 micrometer). The major faces of the tabular grains can lie in either {111} or {100} crystal planes. The mean ECD of tabular grain emulsions rarely exceeds 10 micrometers and more typically is less than 5 micrometers.
In their most widely used form tabular grain emulsions are high bromide {111} tabular grain emulsions. Such emulsions are illustrated by Kofron et al U.S. Pat. No. 4,439,520; Wilgus et al U.S. Pat. No. 4,434,226; Solberg et al U.S. Pat. No. 4,433,048; Maskasky U.S. Pat. Nos. 4,435,501; 4,463,087; and 4,173,320; Daubendiek et al U.S. Pat. Nos. 4,414,310 and 4,914,014, Sowinski et al U.S. Pat. No. 4,656,122; Piggin et al U.S. Pat. Nos. 5,061,616 and 5,061,609; Tsaur et al U.S. Pat. Nos. 5,147,771; ""772; ""773; 5,171,659; and 5,252,453; Black et al U.S. Pat. Nos. 5,219,720 and 5,334,495; Delton U.S. Pat. Nos. 5,310,644; 5,372,927; and 5,460,934, Wen U.S. Pat. No. 5,470,698; Fenton et al U.S. Pat. No. 5,476,760; Eshelman et al U.S. Pat. Nos. 5,612,175; and 5,614,359; and Irving et al U.S. Pat. No. 5,667,954.
Ultrathin high bromide {111} tabular grain emulsions are illustrated by Daubendiek et al U.S. Pat. Nos. 4,672,027; 4,693,964; 5,494,789; 5,503,971; and 5,576,168; Antoniades et al U.S. Pat. No. 5,250,403; Olm et al U.S. Pat. No. 5,503,970; Deaton et al U.S. Pat. No. 5,582,965; and Maskasky U.S. Pat. No. 5,667,955. High bromide {100} tabular grain emulsions are illustrated by Mignot U.S. Pat. Nos. 4,386,156 and 5,386,156.
High chloride {111} tabular grain emulsions are illustrated by Wey U.S. Pat. No. 4,399,215; Wey et al U.S. Pat. No. 4,414,306; Maskasky U.S. Pat. Nos. 4,400,463; 4,713,323; 5,061,617; 5,178,997; 5,183,732; 5,185,239; 5,399,478 and 5,411,852; and Maskasky et al U.S. Pat. Nos. 5,176,992 and 5,178,998. Ultrathin high chloride {111} tabular grain emulsions are illustrated by Maskasky U.S. Pat. Nos. 5,271,858 and 5,389,509.
High chloride {100} tabular grain emulsions are illustrated by Maskasky U.S. Pat. Nos. 5,264,337; 5,292,632; 5,275,930 and 5,399,477; House et al U.S. Pat. No. 5,320,938; Brust et al U.S. Pat. No. 5,314,798; Szajewski et al U.S. Pat. No. 5,356,764; Chang et al U.S. Pat. Nos. 5,413,904 and 5,663,041, Oyamada U.S. Pat. No. 5,593,821; Yamashita et al U.S. Pat. Nos. 5,641,620 and 5,652,088; Saitou et al U.S. Pat. No. 5,652,089; and Oyamada et al U.S. Pat. No. 5,665,530. Ultrathin high chloride {100} tabular grain emulsions can be prepared by nucleation in the presence of iodide, following the teaching of House et al and Chang et al, cited above.
When the silver halide element is a color element it also contains at least one dye forming coupler which reacts with oxidized color developer to form image dye. Image dye-forming couplers which may be included in the element such as couplers that form cyan dyes upon reaction with oxidized color developing agents are described in such representative patents and publications as: xe2x80x9cFarbkuppler-eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen, Band III, pp. 156-175 (1961) as well as in U.S. Pat. Nos. 2,367,531; 2,423,730; 2,474,293; 2,772,162; 2,895,826; 3,002,836; 3,034,892; 3,041,236; 4,333,999; 4,746,602; 4,753,871; 4,770,988; 4,775,616; 4,818,667; 4,818,672; 4,822,729; 4,839,267; 4,840,883; 4,849,328; 4,865,961; 4,873,183; 4,883,746; 4,900,656; 4,904,575; 4,916,051; 4,921,783; 4,923,791; 4,950,585; 4,971,898; 4,990,436; 4,996,139; 5,008,180; 5,015,565; 5,011,765; 5,011,766; 5,017,467; 5,045,442; 5,051,347; 5,061,613; 5,071,737; 5,075,207; 5,091,297; 5,094,938; 5,104,783; 5,178,993; 5,813,729; 5,187,057; 5,192,651; 5,200,305 5,202,224; 5,206,130; 5,208,141; 5,210,011; 5,215,871; 5,223,386; 5,227,287; 5,256,526; 5,258,270; 5,272,051; 5,306,610; 5,326,682; 5,366,856; 5,378,596; 5,380,638; 5,382,502; 5,384,236; 5,397,691; 5,415,990; 5,434,034; 5,441,863; EPO 0 246 616; EPO 0 250 201; EPO 0 271 323; EPO 0 295 632; EPO 0 307 927; EPO 0 333 185; EPO 0 378 898; EPO 0 389 817; EPO 0 487 111; EPO 0 488 248; EPO 0 539 034; EPO 0 545 300; EPO 0 556 700; EPO 0 556 777; EPO 0 556 858; EPO 0 569 979; EPO 0 608 133; EPO 0 636 936; EPO 0 651 286; EPO 0 690 344; German OLS 4,026,903; German OLS 3,624,777. and German OLS 3,823,049. Typically such couplers are phenols, naphthols, or pyrazoloazoles.
Couplers that form magenta dyes upon reaction with oxidized color developing agent are described in such representative patents and publications as: xe2x80x9cFarbkuppler-eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen, Band III, pp. 126-156 (1961) as well as U.S. Pat. Nos. 2,311,082 and 2,369,489; 2,343,701; 2,600,788; 2,908,573; 3,062,653; 3,152,896; 3,519,429; 3,758,309; 3,935,015; 4,540,654; 4,745,052; 4,762,775; 4,791,052; 4,812,576; 4,835,094; 4,840,877; 4,845,022; 4,853,319; 4,868,099; 4,865,960; 4,871,652; 4,876,182; 4,892,805; 4,900,657; 4,910,124; 4,914,013; 4,921,968; 4,929,540; 4,933,465; 4,942,116; 4,942,117; 4,942,118; 4,959,480; 4,968,594; 4,988,614; 4,992,361; 5,002,864; 5,021,325; 5,066,575; 5,068,171; 5,071,739; 5,100,772; 5,110,942; 5,116,990; 5,118,812; 5,134,059; 5,155,016; 5,183,728; 5,234,805; 5,235,058; 5,250,400; 5,254,446; 5,262,292; 5,300,407; 5,302,496; 5,336,593; 5,350,667; 5,395,968; 5,354,826; 5,358,829; 5,368,998; 5,378,587; 5,409,808; 5,411,841; 5,418,123; 5,424,179; EPO 0 257 854; EPO 0 284 240; EPO 0 341 204; EPO 347,235; EPO 365,252; EPO 0 422 595; EPO 0 428 899; EPO 0 428 902; EPO 0 459 331; EPO 0 467 327; EPO 0 476 949; EPO 0 487 081; EPO 0 489 333; EPO 0 512 304; EPO 0 515 128; EPO 0 534 703; EPO 0 554 778; EPO 0 558 145; EPO 0 571 959; EPO 0 583 832; EPO 0 583 834; EPO 0 584 793; EPO 0 602 748; EPO 0 602 749; EPO 0 605 918; EPO 0 622 672; EPO 0 622 673; EPO 0 629 912; EPO 0 646 841, EPO 0 656 561; EPO 0 660 177; EPO 0 686 872; WO 90/10253; WO 92/09010; WO 92/10788; WO 92/12464; WO 93/01523; WO 93/02392; WO 93/02393; WO 93/07534; UK Application 2,244,053; Japanese Application 03192-350; German OLS 3,624,103; German OLS 3,912,265; and German OLS 40 08 067. Typically such couplers are pyrazolones, pyrazoloazoles, or pyrazolobenzimidazoles that form magenta dyes upon reaction with oxidized color developing agents.
Couplers that form yellow dyes upon reaction with oxidized color developing agent are described in such representative patents and publications as: xe2x80x9cFarbkuppler-eine Literature Ubersicht,xe2x80x9d published in Agfa Mitteilungen; Band III; pp. 112-126 (1961); as well as U.S. Pat. Nos. 2,298,443; 2,407,210; 2,875,057; 3,048,194; 3,265,506; 3,447,928; 4,022,620; 4,443,536; 4,758,501; 4,791,050; 4,824,771; 4,824,773; 4,855,222; 4,978,605; 4,992,360; 4,994,361; 5,021,333; 5,053,325; 5,066,574; 5,066,576; 5,100,773; 5,118,599; 5,143,823; 5,187,055; 5,190,848; 5,213,958; 5,215,877; 5,215,878; 5,217,857; 5,219,716; 5,238,803; 5,283,166; 5,294,531; 5,306,609; 5,328,818; 5,336,591; 5,338,654; 5,358,835; 5,358,838; 5,360,713; 5,362,617; 5,382,506; 5,389,504; 5,399,474; 5,405,737; 5,411,848; 5,427,898; EPO 0 327 976; EPO 0 296 793; EPO 0 365 282; EPO 0 379 309; EPO 0 415 375; EPO 0 437 818; EPO 0 447 969; EPO 0 542 463; EPO 0 568 037; EPO 0 568 196; EPO 0 568 777; EPO 0 570 006; EPO 0 573 761; EPO 0 608 956; EPO 0 608 957; and EPO 0 628 865. Such couplers are typically open chain ketomethylene compounds.
The Photographic elements of the invention can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image and can then be processed to form a visible dye image as already described above. The elements as discussed above may serve as origination material for image scanning to produce an electronic rendition of the capture image, and subsequent digital processing of that rendition to manipulate, store, transmit, output, or display electronically that image. A number of modifications of color negative elements have been suggested for accommodating scanning, as illustrated by Research Disclosure, September 1994, Item 36544, and Research Disclosure, September 1996, Item 38957, Section XIV. Scan facilitating features. These systems to the extent compatible with the color negative element constructions described above are contemplated for use in the practice of this invention. Further examples of such processes and useful film features are also described in U.S. Pat. Nos. 5,840,470; 6,045,938; 6,021,277; EP 961,482 and EP 905,651.